Which of these series combination of resistors would replace a single 120-ohm resistor?

When resistors are connected in a series circuit, their individual resistance values add up sequentially to form the total resistance. The formula is simply R_total = R1 + R2 + R3, and so on. To find which combination accurately replaces a single 120-ohm resistor, we must calculate the total for each option. Five 24-ohm resistors wired in series yield exactly 120 ohms (5 x 24 = 120). Watch out for distractors like 'Two 240-ohm resistors.' This would equal 120 ohms only if the components were wired in parallel, not in series.